The present invention relates to drive mechanisms for conveyor belt systems and, more particularly, to a lubricator device for applying a lubricating oil on the conveyor belt used in a conveyor belt system.
Conveyor belt systems are well-known in the art. They are commonly used in applications where it is desired to keep an item moving for an extended period of time within a contained environment, e.g., a product traveling through a processing zone for cooling, heating or any other process applied to the product. As will be recognized by those skilled in the art, a conveyor belt system typically consists of an endless conveyor belt traveling along a path defined by a plurality of tracks or rails. The conveyor belt is supported by the tracks and the product is supported on the conveyor belt whereby the product travels along with the belt on top of the tracks.
Spiral systems are one type of conveyor belt system wherein the conveyor belt travels through concentric stacked helical paths whereby an item travels upward in elevation along the helical paths and/or downward in elevation along the helical paths. These systems typically utilize a cage (sometimes known as a “drum”) for driving the conveyor belt. More particularly, the cage is centrally positioned within the helical path, and may include a plurality of circumferentially-spaced vertical driving bars which contact the inner edge of the belt to impart a driving force thereto. As the cage rotates, the conveyor belt is pulled along its helical path.
In many spiral systems, the cage extends from and is supported by a centrally-located shaft. In turn, the shaft is rotatably supported upon a stationary frame. A drive mechanism is connected to the cage, and rotates the cage with respect to the frame. As the drive mechanism turns the cage, the cage contacts/drives the belt through the helical pathway of the conveyor belt system. Smaller cages often times utilize a center drive mechanism which directly communicates with the center shaft, resulting in rotation of the cage. Larger cages typically utilize a chain and tooth arrangement whereby the chain extends around the circumference of the cage and engages teeth located on the circumference of such cage. The chain in turn communicates with a drive motor.
In spiral conveyor systems, the belt runs continuously from a discharge region of the cage to an infeed region to repeat the spiral conveying. The path between the discharge region and the infeed region of the cage is called “the return path.” In the return path, the conveyor belt runs in the opposite direction to the belt supported on the spiral path of the cage. Moreover, in all cases when the infeed is not aligned with the discharge, the belt must be traversed along a curved return path.
In all conveyor systems, (spiral or otherwise), the friction between the belt and the track support system is an extremely important consideration. As the friction decreases, the performance of the system improves. As is generally known, friction between two surfaces is a factor of the finish and the material that the two surfaces are made from. Every material and surface has a Coefficient of Frication (COF) that is a measure by a number from 0.0 to 0.5. Traditionally, the tracks of typical conveyor systems are covered with ultra-high-molecular-weight polyethylene (UHMW) strips, called “wear strips,” that have a Coefficient of Friction of 0.22.
In many cases, this Coefficient of Friction increases due to debris and dirt accumulation on the tracks. When this COF increases, the performance of the system degrades. Accordingly, most conveyor systems utilize some type of lubricator device to add oil to the track to reduce the COF as much as possible.
A typical device for adding oil to the tracks applies a thin film of oil directly to the bottom of the belt and the belt carries the oil to the tracks. The application of the oil is done by a set of brushes at the point where the belt is up-side-down and accessible.
However, with such prior art lubricating devices, the oil is fed by gravity and, therefore, the amount of oil applied is not accurate. This challenge of applying oil is even greater in spiral systems, since the oil is applied to the belt at a location at the bottom of the spiral. In this case, a large amount of oil is necessary to make sure the tracks are lubricated along the entire length of the spiral. As a result, excess oil frequently drips on the floor and accumulates on the lower tracks potentially contaminating the product on the belt.
Accordingly, there is a need in the art for a simple lubricating device to provide an accurate amount of oil to the conveyor belt/track interface of a conveyor system. It would also be desirable for the device to be clean and non-contaminating to the products being conveyed on the system.